public class e4_23{
  public static void main(String args[]){
  Rational r1=new Rational();
  r1.setNumerator(1);
  r1.setDenominator(5);
  Rational r2=new Rational();
  r2.setNumerator(3);
  r2.setDenominator(2);
  Rational result=r1.add(r2);
  int a=result.getNumerator();
  int b=result.getDenominator();  
  System.out.println("1/5+3/2 = "+a+"/"+b);
  result = r1.sub(r2);
  a=result.getNumerator();
  b=result.getDenominator();
  System.out.println("1/5-3/2 = "+a+"/"+b);
  result = r1.muti(r2);
  a=result.getNumerator();
  b=result.getDenominator();
  System.out.println("1/5*3/2 = "+a+"/"+b);
  result = r1.div(r2);
  a=result.getNumerator();
  b=result.getDenominator();
  System.out.println("1/5÷3/2 = "+a+"/"+b);
  int n=10,k=1;
  System.out.println("计算2/1+3/2+5/3+8/5+13/8+...的前"+n+"项和.");
  Rational sum=new Rational();
  sum.setNumerator(0);
  Rational item=new Rational();
  item.setNumerator(2);
  item.setNumerator(1);
  while(k<n){
	sum=sum.add(item);
	k++;
	int fenzi=item.getNumerator();
	int fenmu=item.getDenominator();
	item.setNumerator(fenzi+fenmu);
	item.setDenominator(fenzi);
	}
  a=sum.getNumerator();
  b=sum.getDenominator();
  System.out.println("用分数表示:");
  System.out.println(a+"/"+b);
  double doubleResult=(a*1.0)/b;
  System.out.println("用小数表示:");
  System.out.println(doubleResult);
 }
}



